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123 lines
2.9 KiB
123 lines
2.9 KiB
Cart = Struct.new(*%i[ x y dir turns ])
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map = ARGF.read.chomp.lines.map(&:chomp).map(&:chars)
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carts = []
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map.each.with_index {|row,y|
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row.each.with_index {|i,x|
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carts << Cart.new(x, y, i, 0) if %w[ ^ v < > ].include?(i)
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}
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}
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loop do
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carts.sort_by {|cart|
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[cart.y, cart.x]
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}.each do |cart|
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case cart.dir
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when ?^
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cart.y -= 1
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crashes = carts.select {|candidate| candidate.x == cart.x && candidate.y == cart.y }
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carts.delete_if {|candidate| crashes.include?(candidate) } if crashes.size > 1
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case map[cart.y][cart.x]
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when ?\\
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cart.dir = ?<
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when ?/
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cart.dir = ?>
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when ?+
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case cart.turns % 3
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when 0
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cart.dir = ?<
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when 1
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when 2
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cart.dir = ?>
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end
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cart.turns += 1
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end
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when ?v
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cart.y += 1
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crashes = carts.select {|candidate| candidate.x == cart.x && candidate.y == cart.y }
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carts.delete_if {|candidate| crashes.include?(candidate) } if crashes.size > 1
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case map[cart.y][cart.x]
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when ?\\
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cart.dir = ?>
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when ?/
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cart.dir = ?<
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when ?+
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case cart.turns % 3
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when 0
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cart.dir = ?>
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when 1
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when 2
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cart.dir = ?<
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end
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cart.turns += 1
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end
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when ?<
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cart.x -= 1
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crashes = carts.select {|candidate| candidate.x == cart.x && candidate.y == cart.y }
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carts.delete_if {|candidate| crashes.include?(candidate) } if crashes.size > 1
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case map[cart.y][cart.x]
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when ?\\
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cart.dir = ?^
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when ?/
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cart.dir = ?v
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when ?+
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case cart.turns % 3
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when 0
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cart.dir = ?v
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when 1
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when 2
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cart.dir = ?^
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end
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cart.turns += 1
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end
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when ?>
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cart.x += 1
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crashes = carts.select {|candidate| candidate.x == cart.x && candidate.y == cart.y }
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carts.delete_if {|candidate| crashes.include?(candidate) } if crashes.size > 1
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case map[cart.y][cart.x]
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when ?\\
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cart.dir = ?v
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when ?/
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cart.dir = ?^
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when ?+
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case cart.turns % 3
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when 0
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cart.dir = ?^
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when 1
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when 2
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cart.dir = ?v
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end
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cart.turns += 1
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end
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end
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# puts map.map.with_index {|row,y|
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# row.map.with_index {|i,x|
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# cart = carts.find {|cart| cart.x == x && cart.y == y }
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# cart ? cart.dir : i
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# }.join
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# }.join("\n")
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# puts
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# crashes = Hash.new(0)
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# carts.each {|cart| crashes[[cart.x, cart.y]] += 1 }
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# crashes = crashes.select {|_,v| v > 1 }.map(&:first)
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# crashes.each do |(x,y)|
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# p x
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# p y
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# carts.delete_if {|cart| cart.x == x && cart.y == y }
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# end
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if carts.size == 1
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p carts
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exit
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end
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# if crashes.values.any? {|v| v > 1 }
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# p crashes.find {|_,v| v > 1 }
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# exit
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# end
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end
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# p carts
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# sleep 1
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end
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